Gliederung

Objective

The new proGAV represents the combination of a new adjustable differential-pressure unit in series with a gravitational device.Through its construction principle, the proGAV should be capable of avoiding the main disadvantages of other so-called „programmable“ valves: The burden of the necessity for repeated X-ray-controls, the sensivity to maladjustments in the MR, the ongoing danger of overdraining of other adjustable differential-pressure-valves and the high probability of obstruction by elevated subcutaneous pressure in adjustable valves with Anti-Siphon-Units.

Methods

We conducted a series of shunts in 29 adult patients with hydrocephalus of different etiologies. In all cases, the proGAV was implanted in ventriculo-peritoneal drainages with frontal burrholes as a first shunt. Primarily we were interested in the reliabity of the adjusted opening pressures in order to avoid the burden of continuous repeated X-ray-controls, in the ability of adjusting the valve transcutaneously safely and the avoidance of maladjustments, for instance by MR-studies. After improving the instruments to measure and readjust the opening pressure, we focussed secondarily on the radiological and clinical results and the possibilities for improvement by readjustments.

Results

After a follow-up of at least 3 months, the clinical results of our small series give evidence for the reliability of the proGAV in avoiding some disadvantages of other adjustable devices. In 7 patients we saw an indication to change the opening-pressure, because of functional underdrainage in 5 cases, but only 3 improved significantly. 2 cases showed signs of overdrainage with transient hygromas. The radiological and clinical final outcome of our little series up to now seems to prove the ability of the new construction principle to avoid surgical replacement of the valve.

Conclusions

The series is too small up to now and the outcome represents only preliminary results, thus a comparison to series with other adjustable valves is not possible. But the new theoretical concept and the first clinical results provide evidence that the proGAV is superior to other devices and may inaugurate a new era of shunting hydrocephalus.